Glass Rain

Portrayal of the exoplanet HD 189733b in Celestia.

For the first time ever, astronomers have managed to discern the colour of a planet outside of our solar system.  The exoplanet, HD 189733b,* is thought to be blue in colour.  They achieved this remarkable discovery by measuring light from the planet when exposed then measuring again when it slipped behind the star.  They noticed a substantial drop of wavelengths corresponding to the colour blue when this happened.  Unfortunately for the possibilities of finding life, this is unlikely to be water.  The planet is thought to be a gas giant which practically hugs its star, giving it a temperature of around 1,000C.  The blue colour probably comes from silicate precipitating in the atmosphere, which reflects light from the star.  That’s right – the planet contains glass rain.  Molten silicate rains horizontally in a sideways direction at around 7,000 km/h.  Just imagine the geographical processes of that planet!  The geology, the chemistry, the…

Every now and then a phrase or an idea leaps out from an astronomical discovery which excites the imagination; ‘glass rain’ is one of those.  I don’t suppose molten silicate is even a particularly unusual occurrence, but it does indicate just how vast and diverse the Universe must be.  This planet is only 63 light years away and scarcely observable as it is – what wonders could exist beyond our reach?  If scientists expand on this technology and method, the possibilities of future discoveries are breathtaking.  It’s moments like these I wish I had become an astrophysicist.

*And scientists wonder why exoplanets never enter the public imagination.

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Death on Mars

As far as we are aware, no organism has ever lived or died on our red neighbour, Mars.  Perhaps evidence will one day emerge of fossilised bacteria hidden within Martian rock.  There is indisputable proof that water once flowed freely on the surface after all, which is one prerequisite for life as we currently understand it.  Some scientists have even suggested life could exist today in underground, water-filled caverns, though I’m not sure how likely this is.  Whatever the truth, nobody has doubted that Mars’ oxygen-less, atmosphere-limited, distant surface would be an easy place to live, but this hasn’t deterred humanity’s persistent dream of one day walking on the red planet.

The Curiosity Rover’s latest discovery, on the other hand, might do just that.  Apparently the level of radiation potential astronauts would endure in both traveling and settling on Mars are far beyond what is considered safe for a human to experience.  Here are some figures, taken from the BBC (measure in millisievert, the unit of equivalent radiation dose):

  •  Annual average: 2.7mSv
  • Whole body CT Scan: 10mSv
  • 6 months on the International Space Station: 100mSv
  • Traveling to and from Mars (excluding time spent on planet): 660mSv

For the average human in a developed country exposed to 2.7mSv a year (so perhaps just over 200mSv in a lifetime), the chances of developing a cancer are around 1 in 4.  If I understand this correctly, this makes the chances of developing a cancer after traveling to Mars far greater than ought to be acceptable.

This, understandably, poses huge problems for the future of space exploration.  It’s incredible that such a haven for life could ever develop on the Earth considering how many dangers exist to us outside of the planet.  While I think some scientists are still optimistic, I find these figures very depressing.  They serve to remind me that the Earth is not a cradle, but a prison.  We are trapped here for each of our tiny lives until the prison walls break down and then even here won’t be inhabitable – once the solar flares beam down, or the surface becomes irradiated by ultra-violet light, or a stray piece of rock slams into us, or…

Mars is a world of death and Earth a world of life.  But Earth is defying the norm of the Universe – how long before it joins Mars?  It’s as if the Universe were designed with the strict intention of making life impossible.

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